I don't know if you can answer that question to a full extent. These are staged matches. These don't train MMA. They may have backgrounds in some sort of martial art, but they don't really fight. Some who have a base in one of these disciplines, could transition into a MMA fighter with lots of training. This goes with anyone who is an athelete, and or has a background in some sort of fight game. There are several NFL players who train in JJ, kick boxing, muay thai, etc... I believe Ray Lewis trains some in MMA, and so does David Akers, he does Jui Jitsu. As far as WWE is concerned my pick would be Stone Cold Steve Austin.
Bruce Buffer announcing his first win in the UFC. Yves Lavinge has called a stop to this contest in 1:48 seconds of the very first round for your winner due to a Stone Cold Stunner. Stone Cold Steeeeeeve Aussssstin.
I used Stone Cold cause he is my all time favorite.